Slack-adjuster



W. W. HUNZICKER.

SLACK ADJUSTER.

APPLICATION FILED 05c. 18, I9l8.

Patented Apr. 13, 1920.

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UNITED STATES PATENT OFFICE.

WALTER W. HUNZICKER, OF MANSFIELD, OHIO, ASSIGNOR TO THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY.

SLACK-ADJUSTER.

Application filed December 18, 1918.

To all whom it may concern:

Be it known that I, WVALTER W. HUN- ZICKER, citizen of the United States, residing at Mansfield, in the county of Richland and State of Ohio, have invented certain new and useful Improvements in Slack-Adjusters, of which the following is a specification.

This invention relates to improvements in slack adjusters used for automatically taking up the slack in brake riggings, due to wear of the brake shoes, wheels and other allied parts.

My invention has special reference to the types of slack adjusters which in practice are mounted between and connected to the live and dead levers of railway brake riggings, or the like, and which are extended by excessive travel of said levers, normally due to the wear of brake shoes and wheels, to maintain a predetermined amount of clearance between the shoes and wheels. In practice, however, due to abnormal conditions, such as heavy car loading and rapid braking. considerable false or excessive travel of the operating levers is frequently occasioned and which if taken up absorbs the proper working clearances between the parts when restored to and operating under normal conditions, thereby causing undue friction between the parts and otherwise rendering the system inefficient.

This invention, therefore, contemplates the embodiment of mechanism in devices above referred to whereby the adjustment for taking up slack may be limited to any suitable or desirable amount regardless of the travel of said levers.

Furthermore, the invention seeks to provide a device of this character which will be simple, compact and durable in construction, effective and eflicient in operation, and which when installed will not require further attention or adjustment.

To the attainment of these ends and the accomplishment of other new and useful objects as will appear. the invention consists in the features of construction, combination of parts, and in'the unique relations and dis position of the latter hereinafter more full described and claimed and shows in the accompanying drawings which illustrate one embodiment of the invention, and in which Figure 1 is a side elevation of a conventional brake rigging showing only such Specification of Letters Patent.

Patented Apr. 13, 1920.

Serial No. 267,310.

parts as are necessary to illustrate the embodiment of one form of the present invention and in which the brakes are shown as released.

Fig. 2 is a view similar to Fig. 1, showing the brakes applied.

Fig. 3 is a part sectional View of the device illustrating the constructional arrange ment and the relation of the various parts.

Fig. +l is a view of a portion of the rod shown partly in section, illustrating a slight modification of the invention.

Similar reference characters refer to similar parts throughout the various views of the drawing.

.lVhile the present invention is shown and described a1 applied to a beamless truck, it is, of course, to be understood that it may be applied to other types of trucks or brake riggings without departing-from the spirit and scope of this invention.

In the drawing two adjacent wh els 1 and- 2 of a truck are supported in the usual manner, each wheel being provided with a brake shoe head 3, which as shown, are pivotally supported by the live and dead levers l and 5 respectively. The dead lever 5 is pivotally supported at its upper end by an arm (3, and the live lever 4 has its corresponding end preferably connected to one end of the pull rod 7, which in turn is connected to the brake actuating mechanism, not shown. The lower ends of the levers are connected in the present case by a slack adjuster embodying the preferred form of my invention and which is adapted to transmit the force applied and carry the brake shoes into and out of contact with'the periphery of the wheels in the usual manner. This slack adjuster is, as shown more fully in Fig. 3, composed of two telescoping parts, one of which is a solid rod 10, pivotally connected at 11 to the lower end of the live lever 4, and telescopes within the hollow portion 12 of the member 13. The end of the member 13 is pivotally connected at 14 to the lower end of the dead lever 5. The member 13 is provided with an enlarged chamber 15, usually open at the bottom within which is positioned a holding device comprising as shown, a plurality of grips 16 through which the member 10 freely passes when moved in one direction under normal conditions. A spring 17 is compressed within the chamber and exerts pressureagainst the grips thereby to maintain the same in a normally canted or holding position, as shown, to interlock the parts 10 and 13 against relative movement in one directionv in the manner well understood in the art. Any suitable or well known means may be provided for releasing and holding the grips against a stop v18, where they will permit free relative movement ofthe mem-- system. An operating mechanism is therefore incorporated with the telescoping members above described to automatically extend the latter by excessive movement of said levers to maintain a predetermined amount of clearance between the brake shoes and the peripheries of the wheels. This operating mechanism comprises in the present instance an adjusting bar 20, having a bent up portion 21 provided with an elongated slot 22, through which passes the pivot pin 23, which supports one end of said bar. The purpose of this slot, which will here- 'inafter be designated as the lost motion slot, is to provide for a limited movement of the levers 4 and 5 when moving the brake shoes into and out of engagement with the wheels and under normal operating conditions to maintain a predetermined clearance between the parts without engaging or affecting the operating mechanism.

The opposite end of the adjusting 'bar 2O carries a movable part 20 which is preferably secured to the body portion of the bar by bolts 20 passing through the slot 20 formed in the bar, as shown. This connection provides for movably adjusting the part 20 to various positions on the body portion of the bar to compensate for slight difi'erences in brake riggings, or the like, and to variably control or I regulate the amount ..of slack which can be taken up at any one. time, as will be described hereinafter.

The movable part 20 comprises a lateral arm 24 and a longitudinal arm 24 provided with a slot 28 and which latter arm at the outer end of the slot forms a shoulder 30. The lateral arm 24 extends through the slot 25 into the barrel 12 and is maintained in spaced relation with the end 10 of the rod 10. Movably mounted in the barrel intermediate the arm 24 and the end of the rod is a clutch 26 provided with an extension 27, which passes through the slot 25 and extends within the slot 28 formed in the part 20 and which is adapted to engage and cooperate with the shoulder 30. A spring 29 is compressed between the arm 24 and the clutch 26, and holds the clutch in a normally canted or holding position as shown when the extension 27 is in engagement with the shoulder 30 and thus holds the clutch in position against movement in one direction and by reason of said engagement prevents movement of the bar 20 in the same direction by a wedging or biting action of the clutch 26 against the surfaces of the barrel. 'The bar and clutch however are free to move in the opposite direction, and it is to be noted that movement of the clutch is limited by the space 31 and that after the clutch has moved through this space 31 continued movement of the bar 20 merely compresses the spring 29, the shoulder 30 moving out of engagement with the clutch extension 27. The space 31 through which the clutch 26 moves determines the maximum amount of extension of the parts 10 and 13 to take up the slack at any one time. This space may be increased or decreased to accordingly limit the extension of said parts by adjusting the part 20 to various positions on the body portion of the bar 20.

Fig. 4 shows a modified form of the invention and in which the end of the rod 10 i built up, or laminated, by removably securing thereto a plurality of thin washers 32, the number of which may be increased or decreased thereby to vary the space 31 to obtain any desirable maximum adjustment of the parts 10 and 13.

The bar 20 is shown as operating through an opening or guide 37, which holds the bar in proper working position and provides a shoulder 36 which serves as a rest to support the bar in case of accidental removal from the pin 23.

'In order that the invention may be thoroughly understood, a brief statement of the operation of the present disclosure is as follows :When the brakes are released, the operating levers are disposed as shown in Fig.1, and the brake shoes held out ofengagement with the wheels. For applying the brakes the upper part of the live lever 4 is moved toward the right and swings about the pivot point 11 thus causing the adjacent brake shoe to move into engagement with the adjacent wheel and simultaneously with such engagement the lower end of the lever 4 moves to the left and this movement is transmitted through the slack adjuster parts 10 and 13 to the dead lever 5, the lower end of which swings to the left about the upper pivotal point with the member 6 and brings the opposite brake shoe into enga ement with the adjacent wheel as shown in 1g. 2.' The above described movement of the live lever will carry the pin 23 from. one end of its opposite end without. imparting any movement to the adjusting bar 20, providing the clearance between the brake shoes and wheels is proper. Continued operation of the brake however is accompanied by shoe wear which permits excess travel of the live lever beyond the amount allowed by the lost motion slot 22, thereby causing the pin 23 to act against the end 34 of the lost mo tion slot and cause the bar 20 to move outwardly, thus advancing the clutch 26 through a part of the space 31, equal in distance to the amount of excess travel of the pin 23, and by engaging the walls of the barrel as hereinbefore stated, holds the bar 20 in extended or advanced position relatively to the member 13. On release of the brakes, the usual return springs not shown, will restore the levers to their normal po sitions and the brake shoes out of contact with the wheels. During the return of the parts to normal position the pin 23 moves to the opposite end of the lost motion slot, which as above stated has been advanced, (see dotted line position, Fig. 2), and into engagement with the end 35 of the slot. At this point the shoes are out of engagement with the wheel and the proper clearances allowed by the lost motion slot established. The pin 23 is now bearing against the end 35 of the slot and acts as a fulcrum since the bar 20 is held stationary relatively to the part 13, and 27 is engaging 30. As the upper end of the live lever continues its movement to full return position, the lower end ofsaid lever operates to elongate or expand the slack adjuster; that is, the member 10 is withdrawn from the part 13 and to an amount exactly equal to the distance taken up by the clutch 26. This operation reestablishes the space 31, which determines the maximum possible single adjustment. Attention is called to the fact that in the above operation the clutch 26 is advanced toward the end 10 of the rod but not into engagement therewith, and that when no unusual conditions prevail the foregoing operation will continue periodically throughout the lifetime of the shoes. By excess movement of the bar 20, caused by false travel of the live lever, when applying the brakes under abnormal conditions as. for instance overloading the cars, and which it is not desired to take up, the movement of the clutch 26 is limited by engagement with the end 10 of the rod, thereby limitingthe amount of take-up or adjustment. Further travel of the bar operates to compress the spring 29, the shoulder 30 of the bar moving out of engagement with the extension 27 of the clutch. Upon release of the brakes by return movement of the live lever the bar 20 will be retracted by the action of the spring 29 against the projection 24 of said bar until the shoulder 30 of the latter engages the extension 27 of the clutch, thereby arresting further movement or retraction of the bar and by continued movement of the live lever the pin 23 will be moved toward and into engagement with the opposite end of the lost motion slot and act as a fulcrum for the live lever, whereby further movement of the latter will operate to extend the slack adjuster as hereinbefore stated.

Thus it will be noted that the adjustment or extension of the slack adjuster is limited by the space 31 regardless of the amount of false or excessive movement of the levers and that this adjustment may be varied by increasing or decreasing the space as herein provided.

hen it is desired to replace worn out shoes, the holding device 16 is released by bringing the grip into engagement with the stop 18 by means of a pry introduced through the. bottom or other convenient opening in the housing 15 and the rod 10 is moved into engagement with the clutch 26, and continued pressure upon the rod will cause the whole mechanism to telescope until its initial condition is reached, at which point there will be sufficient clearance to reinstall' new shoes.

Having fully described my invention and illustrated one embodiment of the same, I do not wish to be limited to the detai s of the construction shown since these can be changed without departing from the spirit and scope of the invention.

I claim as my invention 1. A slack adjuster comprising two rela tively movable parts adjustable to change its length permanently to hold slack taken up thereby, in combination with mechanism operating to extend said parts proportional to slack, but adjustable to limit said extension to take up slack not to exceed a predetermined amount. I 2. A slack adjuster comprising two relatively movable parts adjustable to change its length permanently tohold slack taken up thereby, in combination with mechanism adapted to extend said parts to take up slack of varying amounts up to a predetermined maximum amount.

3. A slack adjuster comprising two relatively movable parts adjustable to change clutch associated with one of said parts and having movement toward and limited by engagement with the other part.

5. A slack adjuster comprising two relatively movable p'arts'in telescopic relation adjustable to change its length to take up slack, in combination with mechanism operable to adjust said parts to take up slack, said mechanism comprising a clutch nor mally movable in one direction carried by one-of said parts, an adjusting bar movable in one direction for actuating the clutch and normally held against movement in the opposite direction by engagement with the clutch, and resilient means engaging the bar and the clutch and holding both in normal operative position. i

6. A slack adjuster comprising two relatively movable parts in telescopic relation adjustable to change its length to hold slack taken up thereby, in combination with mechanism operable to adjust said parts to take up slack, said mechanism comprising a clutch associated with one of saidparts and having an extension, an adjusting bar provided with a shoulder to engage said extension, and a spring compressed between a surface of the bar and the clutch and co-acting with, the shoulder to maintain the clutch in normal holding position.

7. A slack adjuster comprising two relatively movable parts adjustable to take up slack, in combination with operating mechanism supported thereby for adjusting the parts, said mechanism comprisinglpositive gripping means normally movable in one direction only, an adjusting bar for actuat-' ing said gripping means, and yieldable means normally maintaining the bar in position relatively to said gripping means and holding the latter in engagement with one of said parts.

8. A slack adjuster comprising two relatively movable parts adjustable to take up slack, in combination with operating mechanism for adjusting said parts, said mechanism comprising positive gripping means movably arranged within one of said partsand having movement in one direction only limited by engagement with the other part,

and means for variably. limiting the movement of said gripping means.

9. A slack adjuster embodying two relatively movable parts adjustable to take up slack, and means holding said parts against relative movement in one direction but permitting movement thereof in the opposite direction, in combination with mechanism adapted to adjust said parts to take up a predetermined amount of slack or any portion thereof.

10. A device of the character described embodying two parts adjustablv extensible to take up slack, and means acting to maintain said arts in. extended. position when adjusted to take up slack, in combinationthereby, in combination with mechanism operable to adjust said parts, said mechanism embodying an adjusting bar, an element having engagement with one of said parts whereby said element may be moved in one direction only to variably adjust said parts and througha predetermined space to obtain the maximum amount of adjustment by movement of said adjusting bar.

12. A device of the character described embodying two relatively movable parts adjustable to take up slack, one of said parts comprising a hollow portion to slidably receive the other part, and means normally holding said parts against relative movement in one direction but permitting movement thereof in the opposite direction, in combination with mechanism operable to adjust said parts to take up slack, said mechanism embodying operating levers, an ad justing bar having a lost motion connection with one'of said levers, and means normally movable in one direction onlyfengaging one of said parts and having a yieldable engagement with said bar whereby the latter is normally maintained in operative posi-v bar connected to one of said levers, and

means slidably engaging the adjuster and havin a yieldable engagement with thebar where y the latter may move relatively in one direction.

14. In an apparatus of the character described, in combination, a live lever, a dead lever, an automatically extensible adjuster connecting said levers near their ends, and adjusting mechanism connecting one of the levers with one of the parts of said adjuster whereby the parts of the latter may be adjustably extended, said mechanism comprising means limiting the extension of said parts at one time.

15. In an apparatus of the character described, in combination, a live lever, a dead lever, an automatically extensible adjuster connecting the levers, an adjusting bar connected to oneof the levers adapted to be movably engaged by excessive travel of said 30 lever to normally extend said adjuster proportional to slack, and means connecting said bar with the adjuster and cooperating with one of the parts of the latter to prevent extension of said adjuster under ab normal conditions to exceed a predetermined amount regardless of the travel of said lever.

16. A slack adjuster comprising two relatively movable parts adjustable to change its length to hold slack taken up thereby, and means .for maintaining said parts in adjusted position, in combination with mechanism operable to adjust said parts to take up slack, said mechanism comprising. a clutch having engagement with one of said parts whereby said clutch may be moved relatively in one direction, and an adjusting bar comprising two parts adjustably secured together for actuating the clutch.

17. A slack adjuster as in claim 16, the two parts of the adjusting bar being secured together by means of a slotted connection whereby the parts may 'be'adjusted to vary the effective length of said bar. 7

18. A slack adjuster comprising two relatively movable parts adjustable to take up slack, and means for maintaining said parts in adjusted position, in combination with mechanism operable to adjust said parts, said mechanism comprising positive gripping means supported by one of said parts and having a limited amount of movement in one direction, and an adjusting bar for actuating the gripping means, said bar comprising a body portion having a movable part secured. thereto for adjustment thereby to change the effective length of said bar.

19. A slack adjuster asinclaim 18, the gripping means having yieldable engagement with a shoulder provided on said mova'ble part whereby movement of the bar may be had additional to the limited movement of said gripping means.

20. In an apparatus of the character described, in combination, a live lever, a dead lever, an automatically extensible adjuster connecting said levers, an adjustin bar comprising two parts adjustable to c ange its effective length and having a lost motion connection with one of said levers, a clutch associated with the bar and having engagement with one of the parts of said adjuster whereby it may be moved relatively in one direction by movement of the bar, and means engaging the bar and the clutch and tending to maintain both in normal operative position.'

21. In a slack adjuster, the combination with two relatively movable parts and means for securing the parts in adjusted position, of a clutch having engagement with one of said parts and movable bodily relatively thereto and into engagement with the other said part for adjusting the parts.

parts in extended position, of an adjusting device supported by one of the parts and movable longitudinally relatively thereto for adjusting the parts, said device being movable in one direction and into engagement with the other of said parts when in normal operative position.

24. In a slack adjuster, the combination with two relatively movable parts adjust-ably extensible to take up slack and means for maintaining said parts in adjusted position, of a clutch slidably carried by one of said parts and arranged to be positioned at various points intermediate the ends of said part and to normally interlock therewith against relative movement in one direction but to engage the other of said parts when moved in the other direction, and resilient means tending to maintain said clutch in locking position.

25. In a slack adjuster, the combination with two relatively movable parts adjustable to take up slack, of a clutch normally interlocked with one of said parts against relative movement in one direction but movable in the opposite direction from one interlocked position to another, and mechanism for moving the clutch into engagement with the other of said parts torelease its interlock with the first of said parts, said mechanism comprising an adjusting bar having engagement with the clutch whereby it may move relatively.

26. In a slack adjuster, the combination with two relatively movable parts adjustable to take up slack and means for maintaining the parts in adjusted position, of a clutch carried by one of said parts and arranged to move longitudinally relative thereto in one direction and to engage and interlock therewith against movement in the opposite direction at various points intermediate its ends, and mechanism for actuating the clutch and moving it into engagement with the other of said parts, said mechanism comprising an adjusting bar, and means interposed between the bar and clutch and operating to maintain the clutch in locking position and providing for movement of the bar relative to the clutch.

27. An adjusting device for brakes comprising a two-part extensible push rod, means for holding the parts against relative movement in one direction, 'and means for extending the parts to take up slack of any amount between zero and a predetermined sion of the parts to (any predetermined."

value.

29. A slack adjuster comprising in combination a two-part extensible push rod, means for holding the parts against relative movement in one direction, an adjusting loar,

and means alternately engaging one of the parts of the push rod and the adjusting bar to extend the parts of the push rod to take up slack.

30. An adjusting device for brakes com prising in combination a two-part extensible push rod, means for. holding the parts against relative movement in one direction,

a slip clutch normally engagingone of the parts, means for releasing the slip clutch and advancing it into engagement with the other push rod part through a predetermined distance, and means engaging the slip clutch to reestablish its engagement with the first mentioned .part of the push rod.

31. An adjusting device for brakes comprising a two-part extensible push rod, means for holding the parts against relative movement in one direction, means normally engaging one of the parts and adapted to be moved into engagement with the other part through a predetermined maximum distance to extend the push rod parts equivalent to the slack up tothe. predetermined maximum amount,

32. An adjusting device for hrakes comprising a two-part extensible push rod, means .for holding the parts against relative movement in one direction, a slip-clutch normally engaging one of the parts, and means for maintaining said clutch out of engagement with the other part a distance equal to the maximum amount of extension of the push rod parts, as descri'bed.

In testimony whereof I a-fiix my signature.

WALTER W. HUNZIGKER. 

